Alkenyl succinic anhydride emulsion

Abstract

In sizing paper and paperboard with an aqueous ASA sizing system, a dispersal is formed comprising an ASA, a water-immiscible carrier, and a cationic water-soluble dispersing agent and when desired, a non-ionic surfactant. The dispersal can be shipped and stored for a prolonged time until use. The dispersal is added to water to form an oil-in-water sizing emulsion. This prepared emulsion is suitable for sizing paper and paperboard directly without the need for additional emulsifying agents or expensive equipment.

We claim: 
     
       1. A method for forming a dispersal product comprising alkenyl succinic anhydride and a cationic water-soluble polyacrylamide dispersing agent in a water-immiscible hydrocarbon carrier, said dispersal product being suitable for addition to water to yield an oil-in-water sizing emulsion, said method comprising: first providing said cationic water-soluble polyacrylamide dispersing agent in a mixture of water and said water-immiscible hydrocarbon carrier;   then removing the water until said mixture contains less than 0.3% water, by weight,   and finally adding sufficient alkenyl succinic anhydride to form said dispersal product, so that said dispersal product has no more than a trace of water.   
     
     
       2. The method of claim 1 in which a nonionic surfactant is added to form said dispersal product. 
     
     
       3. The method of claim 1 or claim 2 in which said alkenyl succinic anhydride is added in an amount so that said dispersal product is at least 90% by weight alkenyl succinic anhydride and less than 0.03% water by weight. 
     
     
       4. A method of preparing a mixture for sizing paper or paper products with alkenyl succinic anhydride comprising: first forming a dispersal product comprising alkenyl succinic anhydride, a water-immiscible hydrocarbon carrier, and cationic water-soluble polyacrylamide dispersing agent, the dispersal product comprising no more than a trace of water; and then adding said dispersal product to water to form an oil-in-water ASA sizing emulsion.   
     
     
       5. The method of claim 1 or 4 in which the water-immiscible hydrocarbon carrier has a molecular weight between 250 and 750 daltons. 
     
     
       6. The method of claim 1 or 4 in which the water-immiscible hydrocarbon carrier has a viscosity between 50 and 700 SUS at 100° F. 
     
     
       7. The method of claim 1 or 4 in which the water immiscible hydrocarbon carrier is an aliphatic hydrocarbon. 
     
     
       8. The method of claim 4 in which said dispersal product comprises no more than 0.03% water by weight. 
     
     
       9. The method of claim 4 or claim 8 in which said dispersal product comprises at least 90% alkenyl succinic anhydride by weight. 
     
     
       10. The method of claim 1 or 4 in which said dispersal product comprises (by weight): a polyacrylamide dispersing agent at 3-30%;   a hydrocarbon carrier at 3-30%; and   a non-ionic surfactant at 0-7%.   
     
     
       11. The method of claim 1 or 4 in which said dispersal product comprises less than 7% of a non-ionic surfactant. 
     
     
       12. The method of claim 11 in which the non-ionic surfactant is a block copolymer of ethylene oxide and propylene oxide. 
     
     
       13. The method of claim 4 in which the dispersal product of alkenyl succinic anhydride is sprayed under pressure into an aqueous mixture to form an oil-in-water emulsion. 
     
     
       14. An alkenyl succinic anhydride dispersal product comprising an ASA, a water-immiscible hydrocarbon carrier, a cationic polyacrylamide water-soluble dispersing agent, and no more than a trace of water. 
     
     
       15. The dispersal product of claim 14 in which the water-immiscible hydrocarbon has a molecular weight between 250 and 750 daltons. 
     
     
       16. The dispersal product of claim 14 in which the water-immiscible hydrocarbon carrier has a viscosity between 50 and 700 SUS at 100° F. 
     
     
       17. The dispersal product of claim 14 in which the hydrocarbon is an aliphatic hydrocarbon. 
     
     
       18. The dispersal product of claim 14 further characterized in that said dispersal comprises no more than 0.03% water by weight. 
     
     
       19. The dispersal product of claim 14 or claim 18 in which said dispersal comprises at least 90% alkenyl succinic anhydride by weight. 
     
     
       20. The dispersal product of claim 14 in which said dispersal comprises (by weight): a polyacrylamide dispersing agent at 3-30%:   a hydrocarbon carrier at 3-30%; and   a non-ionic surfactant at 0-7%.   
     
     
       21. The dispersal product of claim 14 further comprising less than 7% (by weight) of a non-ionic surfactant. 
     
     
       22. The dispersal product of claim 21 in which said non-ionic surfactant is a block co-polymer of ethylene oxide and propylene oxide. 
     
     
       23. The method of claim 1 or 4 in which said dispersal product comprises 45-96% alkenyl succinic anhydride by weight. 
     
     
       24. The dispersal product of claim 14 in which said dispersal product comprises 45-96% alkenyl succinic anhydride by weight.